1. Field of the Invention
This invention relates generally to computer networks, and more particularly provides a system and method for using wireless routing to connect customers to internet service providers.
2. Description of the Background Art
FIG. 1 is a block diagram illustrating a prior art DSL network 100. DSL network 100 includes multiple servers 102 coupled via a computer network 104 to multiple ISPs 106. Each ISP 106 is in turn coupled via virtual customer circuits 110 to an ATM cloud 112 (e.g., AT&T, Sprint, etc.). The ATM cloud 112 is in turn coupled via virtual paths 114 to a DSL access multiplexer (DSLAM) 116 (e.g., Pacific Bell, Covad, Northpoint, etc.). The DSLAM 116 is in turn coupled via phone pairs 118 to subscribers 120.
The DSLAM 116 manages traffic between multiple ISPs 106 and multiple subscribers 120, and manages non-overlapping virtual customer circuits 110 with the ISPs 106. Although the virtual customer circuits 110 may share the same physical line, the DSLAM 116 enables traffic to be sent from each individual subscriber 120 over the virtual customer circuits 110 to the appropriate ISP 106. Similarly, the ISPs 106 can view subscribers 120 as individual virtual customer circuits 110. Every packet being sent to or from the subscriber 120 from or to the connected ISP 106 includes a virtual path identifier (VPI) and a virtual circuit identifier (VCI). A VPI/VCI pair identifies the permanent virtual circuit (PVC) over which the traffic is sent.
A message is kept secure by virtue of the network. That is, whenever a subscriber 120 transmits or receives a message, the message goes straight to the DSLAM 116. Because the phone pairs are physically separate, other subscribers 120 cannot read the message. Similarly, when the DSLAM 116 communicates upward, the messages are maintained logically separate, and thus other subscribers 120 still cannot read the message.
FIG. 2 is a block diagram illustrating an example prior art subscriber 200. Prior art subscriber 200 includes a DSL modem 202 coupling the phone pair 118 to Ethernet 204. The Ethernet 204 is coupled via an intranet to one or more computers 206. In the DSL network 100, the DSL modem 202 is referred to as the “customer premise equipment” or “CPE.” It will be appreciated that, in the Ethernet-shared network, each of the computers 206 within the intranet typically receive and can read each others messages.
For example, FIG. 3 is a block diagram illustrating a prior art Ethernet-shared LAN (intranet) 300. The intranet 300 includes a single coaxial cable 302 with all these computers 1.1-1.254 connected the cable 302. Each computer has an interface card that identifies the media access control (MAC) address. When a computer 1.1-1.254 sends a message, every other computer 1.1-1.254 receives that message. Every other computer 1.1-1.254 uses the MAC address to determine whether that message was intended for it. A unicast message is addressed to a single computer. A broadcast message is addressed to all stations that are listening. Every station listens to two MAC addresses, namely, a unique dedicated MAC address and a broadcast MAC address. For example, a computer sends a broadcast message when a user goes to “Network Neighborhood.” In this example, responses to the broadcast message enable the sending computer to illustrate the network 300. Although broadcast messages are inefficient, they provide an easy technique for gathering information in a shared environment.
Each intranet 300 has a range of IP addresses assigned to it and has tables that identify these addresses. In this example, the IP addresses within the intranet 300 are shown as 1.x addresses. The IP addresses outside the intranet are x.x addresses. To send a message, e.g., a unicast single address message, to another computer within the intranet 300, a computer 1.1-1.254 uses the 1.x address. To send a message outside the intranet 300, i.e., to the computer network 104, e.g., the internet, either the computer 1.1-1.254 transmits the message to the x.x address and the CPE 1.254 recognizes the x.x address as not within the intranet 300, or the sending computer 1.1-1.254 recognizes the x.x address as not within the intranet 300 and addresses the message directly to the CPE 1.254. In either case, the CPE 1.254 transmits the message to phone pair 118. It will be appreciated that, to locate the address of the CPE 1.254, the sending computer may transmit a broadcast message to locate the IP address of the CPE 1.254.
FIG. 4 is a block diagram illustrating an example prior art cable network 400. Prior art cable network 400 includes a server 102 coupled via a computer network 104 to a cable head end 402. The cable head end 402 is coupled via fiber cables 404 to subscribers 410, 412 and 414. A security concern with the cable network 400 is that, when one of the subscribers 410, 412 or 414 transmits a message, the rest of the subscribers 410, 412 and 414 receive and can read the message. A restriction of the cable network 400 is that all subscribers 410, 412 and 414 connected to the head end 402 must be connected to the same ISP, typically, the same party as the cable service provider. In the case where the cable service provider is also the ISP, the cable provider must be responsible for running the cable and for providing internet services.
In any of the networks identified above with reference to FIGS. 1-4, IP routing interconnects the different network segments. Each IP address is limited to a particular size, e.g., 32 bits. Part of the IP address identifies the network, and part of the address identifies the computer within the network. The address can be split to make few huge networks or several little ones. The first and the last IP address typically have special meanings. For example, the first address typically identifies the network access device (e.g., CPE 1.254), and the last address typically identifies a broadcast message. Although a system of fewer networks, each with a larger customer base, is more cost effective, it is often less secure. On the other hand, a system of many networks, each with a small customer base, is more secure but inefficient with address use and network management needs.